Fullerene, carbon nanotubes, graphene, graphite, and the like are low-dimensional nano-materials composed of carbon atoms. That is, carbon atoms arranged in a hexagonal shape may form zero-dimensional fullerene formed of a ball, may form carbon nanotubes one-dimensionally rolled, may form graphene of a two-dimensional monolayer, and may form graphite three-dimensionally stacked.
In particular, graphene has very stable and excellent electrical, mechanical, and chemical characteristics and is a very excellent conductive material in which electrons can move about 100 times faster than in silicon and current flows about 100 times more than in copper. This was demonstrated through experiments in 2004 when a method of separating graphene from graphite was found. Since then, a great deal of research on this matter has been carried out.
Herein, a graphene layer is subject to large-area synthesis in a wafer substrate or a metal substrate, and, thus, in order to apply the graphene layer to an electronic device, a process of transferring the graphene layer to an electrode substrate of the electronic device is needed. At present, as a transfer method of a typical large-area graphene layer, there is a method in which a wafer on which a graphene layer is grown is adhered to a polydimethylsiloxane (PDMS) substrate and while being immersed in an etching solution, the graphene layer is transferred to the PDMS substrate by means of catalytic etching. Through a process of transferring the graphene layer of the PDMS to substrates, such as polyethylen terephthalate, polyimide film, and glass, of various electronic devices, a large-area transfer of the graphene layer can be made. In this transfer method of the graphene layer, the catalytic etching is performed via the etching solution, and, thus, a lot of time for etching is required. In case of a large-area graphene layer (of about 4 inches or greater), a transfer process needs catalytic etching for at least about one or more days. If a graphene layer is commercially manufactured, such a long-time etching process may result in time inefficiency and high cost in mass production of film, and, thus, it may be difficult to apply to actual production. Therefore, for industrial application of a graphene layer, a method of transferring a large-area graphene film with low cost in a short time is highly demanded.